Genetic Diversity of Local and Introduced Sweet Potato [Ipomoea batatas (L.) Lam.] Collections for Agro-morphology and Physicochemical Attributes in Ethiopia
Efficient use of plant genetic diversity is a prerequisite for the development of crop varieties in meeting the challenges of food security and poverty alleviation. Understanding the variation and diversity of the genetic resources of crop species is therefore the first step to efficient utilization and genetic resource conservation. This study was therefore conducted to estimate the genetic diversity of 114 Sweet potato [Ipomoea batatas (L.) Lam] accessions obtained from Nigeria, Asia, Latin America and Local collections along with two improved varieties. Accessions were planted in 2012/13 cropping season at Haramaya University, eastern Ethiopia using Augmented design and evaluated for 17 agro-morphology and physiocochemical traits. Significant differences among accessions were observed for all traits except four. Varying number of accessions obtained from Asia, Nigerian and Ethiopia performed better than improved varieties for all the traits. Heritability in broad sense and genetic advance ranged from 3.68 to 97.64 and 1.27 to 42.21%, respectively. The estimated genetic distance of 6670 pairs of accessions using Euclidean distance varied from 2.04 to 11. The Nigeria and Ethiopia collections were most distant as compared to other pairs of accessions. The dendrograms from Unweighted Pair-group Method with Arithmetic means (UPGMA) resulted in the formation of 12 clusters, which consisted accessions from different sources except Cluster III and XI, which contained accessions only from Asia. The research revealed the possibility of improving the crop through selection and the importance of further maintaining of these accessions for future improvement regardless of their geographical origin. Moreover, varied number of local collections performed better than higher performing improved variety (check) for all the traits and it was evident the presence of wide variation and genetic diversity among local and between other countries accessions. This suggested the importance of further collection, evaluation and maintaining of Sweet potato cultivars used by farmers in different regions of the country, which were introduced at different time.